Kate Hudson had real doubts about taking on the role of a 1940s socialite who accuses her black chauffeur of rape in new drama Marshall, about an early case fought by Thurgood Marshall, years before he became the US's first black Supreme Court Justice. She tells Laura Harding why

Kate Hudson in Marshall, based on the real-life story of the racially charged trial of a black man accused of raping a white woman in 1940s America

KATE Hudson has a cold. It's manifesting itself as a violent, hacking cough that interrupts her train of thought now and again, stopping her mid-sentence, but she is powering on regardless.

"I'm trying to pretend it's not happening," she says, before the hacking gets the best of her again.

She might be better off at home in bed, curled up with a hot drink, but instead she's dressed up in a New York hotel room, her freshly-shorn buzz cut artfully coiffed into a gentle mohawk.

She's dressed in a navy blue vest and trousers, with matching, eye shadow, while a delicate gold necklace bears the names of her two sons – Ryder and Bing. All this trouble is worth it to her, even when she's feeling poorly, because the film she's here to talk about couldn't feel more appropriate for the moment that we are living in.

It's a warm Saturday afternoon in Manhattan, but around the United States a huge controversy is the horizon. The next day scores of NFL players, who are predominantly black, will get down on one knee as the national anthem plays, protesting against police brutality and inequality towards African Americans.

President Trump will say those players should be fired.

It is a divided America we are in, and Hudson (38) is very aware of it. Her new film, Marshall, recounts the real trial of an African American chauffeur in 1941, who was accused of the rape and attempted murder of a Connecticut socialite, played by Hudson.

The title refers to the first black Supreme Court Justice, Thurgood Marshall – played by Black Panther star Chadwick Boseman, who was a 30-year-old lawyer when he defended the chauffeur, played in the film by hit US television series This Is Us's Sterling K Brown.

The case was a real-life sensation, with newspapers detailing every lurid detail with race-baiting language, referring to the accused Joseph Spell as a "coloured servant" or "Negro chauffeur". The language used by the trial's prosecutor, played by Downton Abbey's Dan Stevens, is just as painful and eye-watering – describing Spell as a "lust-mad Negro" who stalked Hudson's character "like a panther".

This kind of racial division doesn't feel a million miles away from where we are now, Hudson says.

"It is so interesting how relevant it is right now, and something that was in 1941 is still as relevant today as it was then. You would think these things would have been something that people learned from, and instead we are still seeing history repeat itself."

She adds: "Sometimes when you're looking at material, you don't how much is true and you don't know how much is sort of stretching to tell the narrative in a way that makes sense in two hours so as an actor you come in with your ideas.

"You say 'I don't know if my character would say this' or 'I think this is actually stretching it a little', but we all had these moments with this case where we were dumbfounded that these things were actually said, they were actually happening.

"It was kind of an amazing history lesson. We must never forget our history, all of it, and when you're acting it out you feel so close to it and you think 'how is that even possible?'

"I think it's important to be a part of movies that make people continue to have the dialogue. It would be amazing if movies could actually inspire younger generations to fight like Thurgood Marshall."

Given the current climate, playing Eleanor Strubing, a white woman who points the finger at a black man, was a tough decision for Hudson.

"There were so many things about this character that gave me pause," she says. "It was something that I had a very hard time relating to in any way. And then when Reggie [Hudlin, the director] talked about the movie he wanted to make and the importance of it, it sort of took me outside of my own moral and ethical codes of how I handle my life and put me into this time and how important it is to tell these stories.

"As an actor sometimes you have to take your own personal beliefs, and you never really set them aside but, when the cameras are rolling, you have to believe in what that character is. That was really challenging and, as an actor, challenge is something that is really enticing.

"I was being asked to play an incredibly complex character that is trapped and lonely and makes a horrible decision that she can't extricate herself from in any way, and those kinds of complexities are interesting to tackle."

She was also compelled by the chance to tell the story of a young Thurgood Marshall, a man who is seen as a pillar of the civil rights movement, but about whom very little is known in is younger years.

"He put himself in so much danger," Hudson says. "It was dangerous for him and he didn't even think about it – it was just he had a trajectory of where he wanted to see the world and how the world should be shaped and he went after that.

"It just takes so much bravery and courage, it's so nice to tell a snippet of his story when he was young."

But for all the weight of the responsibility of telling this tale, the cast managed to find plenty of moments of levity.

"We are telling this heavy story, this important, relevant story, and then as friends, when the cameras were off and everything, it was just us hanging out waiting for the next scene or next shot, and we were singing musicals and having one of the most fun times I've ever had with a cast," Hudson says.

"There was an interesting dichotomy of telling a really important story with people who really cared about what we were creating, and then actually having a complete blast with each other in Buffalo of all places [in New York state].

"The boys had their own little Boyz II Men action happening that I wasn't involved in, but we were all really singing Hamilton. Hamilton [Lin-Manuel Miranda's hip hop musical about Founding Father Alexander Hamilton] was the big one."